Research On Performance Enhancement Technology Of Metasurface Microstrip Antenna

As the cornerstone of the internet of everything,wireless communication system,in which antenna is the most critical element,has been found more and more applications in intelligent driving,smart factory,no man guard storage and other fields.So do the upcoming challenges to the performance of antenna in these new application scenarios,in such a way that antenna system is forced to transform from a spatial energy converter to a multi-functional,high-integrity smart platform for mass production.Because of the limitations on traditional antenna structures,researchers have to search for solutions in crossing fields.The successful electromagnetic applications of metamaterial open up a new direction for antenna design.Metasurface,as a kind of planar metamaterial,shows enhancements on bandwidth,isolation,transmission loss and carries attached features like multibeam,frequency scan or channel multiplexing when combined with antenna and therefore researches on metasurface antenna possess profound significances for future developments of communication technology.This paper focuses on enhancements on radial performance of microstrip antenna by metasurface.The main content includes the following four parts:1.A diamond shaped low profile wideband antenna is proposed.The working mechanism and modal excitation of TM₃₀ metasurface are analyzed based on TCM.By etching center slot to guide mode combination,a C-band miniaturized wideband MTA is designed.For further enhancement,resonating elements and truncation are both introduced to form a diamond shaped MTA.The relative bandwidth is 50%with the peak gain of 9.8d B.The measured results verify the wideband and high gain performances.2.A V-band gap waveguide antenna array is proposed.The working mechanism of gap waveguide is analyzed by equivalent circuit model.A ridge gap waveguide with bed nail units and an invert microstrip line gap waveguide with mushroom units are both designed.The comparison among different transmission structures at V band validate the low transmission loss of gap waveguide.A WR-15 rectangular is selected as feeding source,energy travels into the gap waveguide power divider by transforming structure and excites wideband MTA units to form a wideband antenna array.The measured relative bandwidth is 29%and the measured peak gain is 11.8 d B.3.A antenna array decoupling surface is investigated.By controlling the refractive energy in the near filed,the field cancelling based decoupling surface can produce an interference signal to the mutual coupling from the adjacent units and improve the antenna isolation.Decoupling surfaces for four-unit linear array and six-unit planar array are both modeled here to introduce the design procedures.By extracting amplitude and phase of reflective wave,parametric study is conducted to find out the influence on isolation level.Finally,compared with the antenna array without decoupling surface,the simulation results show that the decoupling surface can provide 20 d B isolation enhancement and preserve its radiation performance at the same time.4.A circular polarized antenna based on polarization converting surface is researched.The proposed structure provides a new design method of circular polarized antenna by transforming linear polarization to circular polarization.